The whole town followed the cortege, Sultana Katima leading it on her bay mare. The crowd roared in its sorrow like the sea on its pebble beach. They buried him overlooking the great grey ocean, and after that it was black cloth and ashes for many months.

Somehow they never came out of that year of mourning. It was more than the death of the ruler; it was that the Sultana continued to rule on alone.

Now Bistami, and everyone else, would have said that Sultana Katima had been the true leader all along, and the Sultan merely her gracious and beloved consort. No doubt that was true. But now, when Sultana Katima of Baraka came into the grand mosque and spoke in the Friday prayers, Bistami was once again uneasy, and he could see the townspeople were as well. Katima had spoken before many times in this manner, but now all felt the absence of the covering angel provided by the lenient Sultan's presence across the river.

This unease communicated itself to Katima, of course, and her talks became more strident and plaintive. 'God wants relations in marriage between husband and wife to be between equals. What the husband can be the wife can be also! In the time of the chaos before the year one, in the zero time, you see, men treated women like domestic beasts. God spoke through Mohammed, and made it clear that women were souls equal to men, to be treated as such. They were given by God many specific rights, in inheritance, divorce, power of choice, power to command their children – given their lives, do you understand? Before the first hegira, before the year one, right in the middle of this tribal chaos of murder and theft, this monkey society, God told Mohammed to change it all. He said, Oh yes, of course you can marry more than one wife, if you want to – if you can do it without strife. Then the next verse says "But it cannot be done without strife!" What is this but a ban on polygamy stated in two parts, in the form of a riddle or a lesson, for men who could not otherwise imagine it?'

But now it was very clear that she was trying to change the way things worked, the way Islam worked. Of course they all had been, all along – but secretly, perhaps, not admitting it to anyone, not even to themselves. Now it faced them with the face of their only ruler, a woman. There were no queens in Islam. None of the hadith applied any more.

Bistami, desperate to help, made up his own hadith, and either supplied them with plausible but false isnads, attributing them to ancient sufi authorities made up out of whole cloth; or else he ascribed them to their Sultan, Mawji Darya, or to some old Persian sufi he knew about; or he left them to be understood as wisdom too common to need ascription. The Sultana did the same, following his lead, he thought, but took most of her refuge in the Quran itself, returning obsessively to the suras that supported her positions.

But everyone knew how things were done in al Andalus, and the Maghrib, and in Mecca, and indeed everywhere across Dar al Islam, from the western ocean to the eastern ocean (which Ibn Ezra now claimed were the two shores of the same ocean, spanning the greater part of the Earth, which was a globe covered mostly by water). Women did not lead prayers. When the Sultana did, it remained shocking, and triply so with the Sultan gone. Everyone said it; if she wished to continue along this path, she needed to remarry.

But she showed no sign of interest in that. She wore her widow's black, and held herself aloof from everyone in the town, and had no royal communications with anyone in al Andalus. The man other than Mawji Darya who had spent the most time in her company was Bistami himself; and when he understood the looks some townspeople were giving him, implying that lie might conceivably marry the Sultana and remove them from their difficulty, it made him feel light headed, almost nauseous. He loved her so much that he could not imagine himself married to her. It wasn't that kind of love. He didn't think she could imagine it either, so there was no question of testing the idea, which was both attractive and terrifying, and so in the end painful in the extreme. Once she was talking to Ibn Ezra when Bistami was present, asking him about his claims concerning the ocean fronting them.

'You say this is the same ocean as the one seen by the Moluccans and Sumatrans, on the other side of the world? How could this be?'

'The world is most certainly a globe,' said Ibn Ezra. 'It's round like the moon, or the sun. A spherical ball. And we have come to the western end of the land in the world, and around the globe is the eastern end of the land in the world. And this ocean covers the rest of the world, you see.'

'So we could sail to Sumatra?'

'In theory, yes. But I've been trying to calculate the size of the earth, using some calculations made by the ancient Greeks, and Brahmagupta of south India, and by my studies of the sky, and though I cannot be sure, I believe it must be some ten thousand leagues around. Brahmagupta said five thousand yoganda, which as I understand it is about the same distance. And the land mass of the world, from Morocco to the Moluccas, I reckon to be about five thousand leagues. So this ocean we look out on covers half the world, five thousand leagues or more. No ship could make it across.'

'Are you sure it is so big as that?'

Ibn Ezra waggled a hand uncertainly. 'Not sure, Sultana. But I think it must be something like that.'

'What about islands? Surely this ocean is not completely empty for five thousand leagues! Surely there are islands!'

'Undoubtedly, Sultana. I mean, it seems likely. Andalusi fishermen have reported running into islands when storms or currents carried them far to the west, but they don't describe how far, or in what direction.'

The Sultana looked hopeful. 'So we could perhaps sail away, and find the same islands, or others like them.'

Ibn Ezra waggled his hand again.

'Well?' she said sharply. 'Do you not think you could build a seaworthy ship?'

'Possibly, Sultana. But supplying it for a voyage that long… We don't know how long it would be.'

' Well,' she said darkly, 'we may have to find out. With the Sultan dead, and no one for me to remarry ' and she shot a single glance at Bistami – 'there will be Andalusi villains thinking to rule us.'

It was like a stab to his heart. That night Bistami lay twisting on his bed, seeing that short glance over and over. But what could he do? How could he be expected to help such a situation? He could not sleep, not the entire night long.

Because a husband would have helped. There was no longer a feeling of harmony in Baraka, and word of the situation certainly had made its way over the Pyrenees, for early in the following spring, when the rivers were still running high and the mountains protecting them still stood white and jagged edged to the south, horsemen came down the road out of the hills, just ahead of a cold spring storm, pouring in from the ocean: a long column of cavalry, in fact, with pennants from Toledo and Granada flying, and swords and pikes at their hips gleaming in the sun. They rode right into the mosque plaza at the centre of town, colourful under the lowering clouds, and lowered their pikes until they all pointed forwards. Their leader was one of the Sultan's elder brothers, Said Darya, and he stood in his silver stirrups so that he towered over the people gathering there, and said, 'We claim this town in the name of the Caliph of al Andalus, to save it from apostasy, and from the witch who threw her spell over my brother and killed him in his bed.'

'The crowd, growing by the moment, stared stupidly up at the horsemen. Some of the townspeople were red faced and tight lipped, some pleased, most confused or sullen. A few of the rabble from the original Ship of Fools were already pulling cobblestones out of the ground.